Process for altering the temperature of aggregates



2 Sheds-Sheet 1 R. M. MCSHEA HNW mY .SS .SS 89u Dec. 13, 1949 Paocnss Fon ALTERINQ THE TEMPERATURE oF AGGREGATES Filed Jan. 19, 1948' E w /m maw W mw M. mw

Dec. 13, 1949 R. M. McsHEA 2,491,194

PROCESS FOR ALTERING THE TEMPERATURE OF AGGREGATES Filed Jan. 19, '1948 2 Sheets-Shoot 2 NVENTOR. 4'4 @a y/-u M. Mc ,sf/5A,

2 1 A BY d Eik- M P TUR/VE KS Patented Dec. 13, 1949 alargar PRocEss Fon ALTERING THE TEM- PERATURE F AGGREGATES noyau M. Mcshea, wichita, Kans. Application January 19, 194s, serial Nd. 3.053

2 Claims. (Cl. 259-159) This invention relates to a process for the preconditioning of aggregates by altering the temperature thereof for use in concrete mixing.

In concrete construction, particularly in large projects such as the construction of large dams and the like, it has been found that the aggregates for the concrete mix exposed to different climatic conditions commonly become either heated to such a degree or have their temperature so lowered that the temperature of the same varies widelyffrom the temperature of the other ingredients of the concrete mix under normal operating conditions, and if used with the other ingredients under these conditions, the mixture temperature will not be uniform. It is highly important that the mixture temperature be uniiorm -as in this way expansion and contraction of the mixture is decreased thereby lessening the danger of expansion cracks.

An object of the invention is to provide a process by which the temperature ofthe aggregates can be uniformly, economically and expeditiously altered as required to be of a temperature suitable for mixing with the other ingredients so that the 'mixture temperature will be substantially uniform.

Another object of the invention is to provide a process in which water is used as a heat interchanging medium and whereby the temperature of the aggregate will be uniformly altered as de- ,v A 2 The invention, with other objects and advantages thereof, will be understood from the following detail description when considered in connectic-n with the accompanying drawings forming part hereof and' illustrating a preferred form of apparatus for carrying out the process.

In the drawings:

Fig. l is a vertical section of an apparatus constructed in accordance with the present invention;' y

Fig. 2 of Fig. 3;

Fig. 3 is a lhorizontal section on the line 3-3 of Fig. 2;

Fig. 4 is a transverse section on the line -it of Fig. 3.

In accordance with the invention, a large amount of the aggregate enclosed within a large vertical tank or silo or a plurality of such tanks or silos, is subjected to the heat interchanging action of water continuously circulatedl throughis a vertical section on the ne 2-2 out the vertical stack or stacks of the aggregates, cold or hot water being employed depending upon whether the temperature of the aggregate is to be lowered or raised, and the circulation of the water throughout the stack or stacks of aggregate being maintained until the temperature of the aggregate has been altered sired andthe moisture content thereof will be uniform.

Another object of the 'invention is to provide a method of the character referred to which can be practiced on' an extensive scale and whereby aggregates suitable for concrete mixing can be.

large scale concrete construction.

Another object of the invention is to provide an apparatus of compartively simple construction that will operate elcientlyto carry out the process.

Another object of the invention is to provide an efllcient apparatus for altering the temperature of aggregates, that will provide for continuously supplying preconditioned aggregates in large quantity to suit the demands of concrete construction on an extensive scale.

Still another object of the invention is to procontinuously supplied to meet the demands of I vide an apparatusfof the character referred to which wi1l` be of compact construction, and in which the units are so arranged as to provide for continuous rapid transfer of the treated aggregates i'roxnv the apparatus to a concrete mixing plant.

to the desired degree suitable for incorporation in the concrete mix. As will be understood, when cold water is employed it acts to absorb and carry oil? heat from the aggregates, while if the temperature ofthe aggregates is'to be raised and hot water is used. the water then serves to transmit heat to the aggregates. The` water is preferably circulated from the lower end of the silor or silos upwardly through the stacks of the aggregates, the water passing through the channels formed by the voids in the lstacks of aggregate, to the upper end of the silos or tanks, and the stacks of aggregate being submerged in water during the circulation of the water through the silos. 'Ihe aggregate to 'be preconditioned is-introduced into the silos at the upper ends ends thereof. Before charging the silos with the aggregate, the silos are filled with water to act as cushioning means-for the falling aggregate. After the temperature of the. aggregate has been altered as desired by the' continued A circulation of the heat interchanging water through the silos in contact.with the stacks .of

aggregate. the circulation of the water is disfA continued and the stacks of aggregate are left standing in time to permit the water in the. silos todrain the silos for a sumcient period of back into the\system, after which the mass of aggregate uniformly alteredV to the desired temperature and of uniform -moisture content, is

. l v4 A the cooling unit is in operation, refrigerant will be circulated through the ,coil Il to cool Athe discharged from the outlet in the lower end .of

the silos and conveyed to a concrete mixing plant, the preconditioned aggregate being introduced into the mixing plant in proper proportion with other-ingredients of the concrete mix, the cement, s and and water.

Referring now to a detailed description of the drawings. the apparatus shown includes a. pair of large vertical tanks or silos I, 2 varranged side by side in spaced relation and suitably supported with their lower'ends elevatedaboveA the iloor level. Each of the silos is open at its upper end. and at its lower e'nd has a lateral discharge l0 particular form of apparatus illustrated in the tric-motor 22. When the motor is in operation. the'oil burner of the heating unit will be operated outlet 2. A vertically slidable gate or valve 4 A is provided for each of the material outlets 2. Any suitable operating means, not shown, is provided for opening and closing each of the gates or valves. and for holding the same in diiierent intermediate positions of adjustment to regulate the discharge of material from the lower ends of the silos'Iand 2. I designates a chute for supplying material to the silos, this chute discharging into a feed spout 6 having two branches 1. oneof said branches leading into each oi the silos. 'I'he spout l is provided with a Divoted valve or gate l for regulating the feed of the aggregates into the tanks. When in the intermediate position shown in Fig. 1 of the drawings,

the aggregatesfwill be supplied to each of the silos. -As will be understood, by' swinging the valve l laterally to engage either side of the spout l, one of the branches 'I will be closed while the other remains open, the arrangement shown providing for simultaneously feeding the aggregates to both of the silos, or to only one as desired.

Apparatus is provided for cooling and heating water for circulation through the silos I and 2 in contact with stacks of aggregate therein. This apparatus'comprlses a tank l having a pipe connection Il to the lower end of the silo I, a branch pipe connection I2 from the pipe connection I0 to the lower end oi' the other silo 2, and overiiow return pipe connections II and IIa leading from the upper part of the silos back to the tank l. Interposed in the'pipe connection I0 is a centrifugal pump I4 for forcing water from the storage tank or reservoir l through the pipe connection Il and branch pipe connection I2 to the lower ends of the silos IA and 2. 4In the diagrammatic showing of the .centrii'ugalpumpV in Fig. l of the drawings. the same is shown below the level of the tank l, but in actual practice the'pump I4 will be'interposed in the pipe connection Il at a point above the level of the lower part of the tank so that when the operation of the centrifugal pump I4 is stopped, water may drain from the silos I and 2 through the pipe connection I., and the branch pipe connection I2 back'to the tank. 'II designates an'electric motor for operating the pump. In the pipe connection Il is a valve I6 and in the branch pipe connection I2 isa valve I'I, these valves providing 'forcutting ofi' the circulation of heat in water to either one of the silos. 'Associated with the water storage tank or reservoir l is a rei'rigerating unit I8. This cooling unit, which is of conventional form, has its coil Il located within the water reservoir 9. 20 designates an electric motor for operatingthe cooling unit. Aswill be understood, when the motor of to heat the water and generate steam. 22 designates a pipe leading from the steam space of the heating unit 2I into the water reservoir l, said pipe having sultableoutlet nozzles 24. 2l is a return pipe connection from the water reservoir 9 to the water chamber of the water heating unit.

Any suitable control means (not. shown) is 4provided for regulating the operation of the' water circulating pump I4l the cooling unit and the heating unit to/maintain the heat interchanging water circulated through the silos at the desired temperature. The control means may be in the form of manually operable switches by which the supply of electric power to the motor Il of the water circulating pump, the motor 2l oi' the refrigerating unit, and the motor 22 of the heating unit, is regulated, or automatic control means may be employed, Either automatic time control 'switch mechanism or `temperature or thermostatic control means may be used. As

. will .be understood, when time control switch mechanism is made use of, the time control switch mechanism would be set "for the period of time desired for the operation of the water circulating pump I4, and then through the conventional stopfstart button, the time control mechanism would be set in operation, and the motor I5 simultaneously started for operation of the water circulating pump I4. The circulating pump and heat interchanging apparatus will then run for a predetermined period of time. at the expiration of which the timing switch mechanism will automatically break the circuit to the motor I5 of the circulating pump and stop the operation of the pump, the water circulating pump then remaining out of operation until the time control switch is re-set and the operation again started.. Instead of automatic time Acontrol means, a. temperature or thermostatic control may :be employed. vIn the case of the temperature or. thermostatic control, the mechanism would be set to break the circuit of the pump I4 when the temperature of the water passing from the silo into the overflow pipe connection or IIa reaches a predetermined degree.

A conveyor 44 is suitably mounted to extend horizontally with its upper stretch disposed directly lbelow the space between the lower ends of the silos I and 2, to receive the treated aggregate discharged from the outlets 3 at -the lower ends of the silos. This conveyor, as shown in the drawings. is provided with apertures 4l extending therethrough so that any excess moisture contained in the aggregate can drain oi! through the apertures in the endless carrier while supported thereon. To facilitate drainage of excess moisture from the aggregate. the series of rollers 46 supporting the upper stretch of the endless carrier 44 are arranged in staggered relation so that the upper stretch of the carrier will be given a vertical undulating movement while passing over the series of rollers. The endless carrier 44 conveys the material to another endless carrier 41 extending at right angles thereto. This endless carrier is shown extending through an opening 48 in a side wall49 of the building 1n which the aggregate treating apparatus hereinbefore described, is housed. The endless carrier 41 transfers the treated aggregate to a concrete mixing plant 50, which is of conventional form and only indicated in a general way, I designates the hoppers to which the diierentingredients of the concrete mix are fed, 52 are the weighing devices, and 53 designates the vusual oscillatory mixing devices of the concrete mixing plant.

In practicing the invention, the storage tank or. reservoir 9 is lled with water through the valve controlled filling inlet 54. Either the cooling unit I8 or the heating unit 2| is set in operation, depending upon whether the aggregate is to be cooled or heated. The circulating pump i4 is next started and water is pumped from the reservoir 9 into the silos l and 2. After the silos have been filled with water to the level of the point of connectionrof the overow pipes il and Ha with the silos, the aggregate to be treated is introduced therein, the pump i4 being kept in opnections being controlled by valves providing for the supply of water from the reservoir to one or more of the silos as desired. When cold water is available from natural sources, the invention .contemplates utilizing this in place of the cool ing unit I8, in such instances the water reservoir being provided with an additional inlet pipe connection for the natural cold water supply.

What I claim is:

1. The method of preconditioning a large mass of conned aggregates consisting of individual particles by altering the temperature thereof for incorporation with other ingredients in a concrete mix, including circulating under pressure eration to 'circulate the heat interchanging water through the silos in contact with the stacks of aggregate until the temperature of the same has been altered as desired. The water circulating pump and the cooling vunit or the heating unit, as the case may be, are then cut out 0f operation.

The treated aggregate is left in the silos a sulthe silo 2 will be cut out of the water circulating circuit.

While a preferred form of apparatus is illustrated in the drawings, it will be understood that minor changes and modifications may be made in the particular construction shown and the apparatus may take other forms as will appeal to those skilled in the art and falling within the scope of the appended claims without departing from the spirit of the invention.

In the particular exempliflcation of the apparatus illustrated in the drawings. a battery ot only two silos for the treatment of the aggregate is shown, but any number of silos may be employed as desired located at dierent pointsv along the endless carrier 44, the heating and cooling apparatus being accordingly increased in capacity with suitable pipe connections between each of the silos and the water reservoir. the pipe cona continuous supply of temperature interchanging fluid in suilicient volume through the mass of aggregates to thoroughly permeate the same and to intermingle with the individual particles constituting -the aggregates in direct contact therewith so that the individual particles and the entire mass of confined aggregates are thoroughly subjected to the temperature interchanging fluid whereby the vtemperature of the mass of aggregates is substantially uniformly altered.

2. The method of preconditioning a large mass of confined aggregates consisting of individual particles by altering the temperature thereof for incorporation with other ingredients in a concrete mix, including circulating under pressure a continuous supply of temperature interchanging uid upwardly in sui`n`cient volume through the mass ofaggregates to thoroughly permeate the same and to intermingle with the individual particles constituting the aggregates in direct contact therewith so that the individual particles and the entire mass of confined aggregates are thoroughly subjected to the temperature interchanging uid whereby the temperature of the mass of aggregates is substantially uniformly altered.

ROYAL M. McSHEA.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 737,079 Chase Aug. 25, 1903 762,869 Allen June 21, 1904 808,599 Cricheld Dec. 26.1905 1,039,654 Dickson Sept. 24, 1912 1,367,719 Schutte Feb. 8, 1921 1,476,243 France '.v-.. Dec. 4, 1923 1,687,227 Powell Oct. 9, 1928 1,787,339 'Clapp Dec. 30, 1930 FOREIGN PATENTS Number Country Date 266,335 Great Britain May 19, 1927 

